Patent Application
20230140962
The present invention relates to a multilayer structure.
Multilayer structures in which two or more layers are laminated are known. As an example, a multilayer structure in which a silver reflecting layer is laminated on a thin glass layer (glass film) is given. Such a multilayer structure has surface hardness, dimensional stability, chemical resistance, lightness, and flexibility. Therefore, thin glass mirrors utilizing such a multilayer structure are capable of projecting a clear image because those thin glass mirrors are not only lightweight and free from problems such as scattering, but are also free from problems with conventional sheet glass mirrors, such as double reflection of images, due to a distance between the glass surface and the metal layer being extremely close.
[Patent Document 1] Japanese Unexamined Patent Application Publication No. 2013-231744
However, such thin glass mirrors are difficult to handle, and have handling issues when installing large area mirrors on buildings and the like.
It is an object of the present invention to provide a large area multilayer structure that can be used as a thin glass mirror.
In one aspect according to the present invention, a multilayered structure includes
a plurality of laminated portions arranged on a base material, wherein the laminated portions each include
resin layer,
a glass layer laminated over the resin layer via an adhesive layer, and
a metal layer formed on a surface of the glass layer, the surface being oriented toward the adhesive layer, wherein a thickness of the glass layer is 10 μm or more and 300 μm or less, and a thickness of the resin layer is 10 μm or more and 1000 μm or less.
According to the disclosed technology, a large area multilayer structure that can be used as a thin glass mirror may be provided.
Hereinafter, an embodiment of the invention will be described with reference to the accompanying drawings. In each of the drawings, the same components are denoted by the same reference numerals, and duplicate descriptions may be omitted.
As illustrated in
In the present embodiment, as an example, a planar shape of a multilayer structure 1 (a shape viewed from the direction normal to an upper surface 20a of the base material 20) is a rectangular shape, a short side direction of the rectangular shape is an X direction, a long side direction of the rectangular shape is a Y direction, and a thickness direction of the multilayer structure 1 is a Z direction. The X, Y, and Z directions are orthogonal to each other. When the planar shape of the multilayer structure 1 is rectangular, for example, the width (X direction) may be approximately 1 m to 10 m, and the height (Y direction) may be approximately 1.5 m to 3.5 m.
In the present embodiment, as an example, in the multilayer structure 1, nine laminated portions 10 are arranged on the upper surface 20a of the base material 20. However, in the multilayer structure 1, the number of the laminated portions 10 arranged on the upper surface 20a of the base material 20 may be two more as desired.
In the multilayer structure 1, each laminated portion 10 is fixed to the upper surface 20a of the base material 20 via an adhesive layer 15. The laminated portions 10 each include a resin layer 11, an adhesive, layer 12, a metal layer 13, and a glass layer 14. The glass layer 14 is laminated over the resin layer 11 via the adhesive layer 12. The metal layer 13 is formed on a surface of the glass layer 14 that is oriented toward the adhesive layer 12.
Although the laminated portion 10 has flexibility, the, multilayer structure 1 as a whole need not necessarily have flexibility. The flexibility required for the multilayer structure 1 as a whole may be provided by adjusting the material and the thickness of the base material 20, for example.
The planar shapes of the resin layer 11, the adhesive layer 12, the metal layer 13, and the glass layer 14 are rectangular, that is, the planar shape of the laminated portion 10 is rectangular as an example in this embodiment.
The multilayer structure 1 can be used, for example, as a mirror, but it is preferable to make joints of the adjacent laminated portions 10 less visible. That is, it is preferable that the laminated portions 10 are arranged on the base material 20 without gaps. However, in practice, it is difficult to make the gap width between the adjacent laminated portions 10 zero, and as illustrated in
The gap S is preferably 10 μm or more and 500 μm or less. By making the gap S 500 μm or less, it is possible to make it difficult to visually identify the joint of the adjacent laminated portions 10. The lower limit is set to 10 μm because a gap of approximately 10 μm is always formed practically even if the plurality of laminated portions 10 are fixed on the base material 20 with a target of the gap S being set to 0 μm. However, if the dimensional accuracy of the individually divided laminated portions 10 can be improved, there is a possibility that the gap S can be made smaller than 10 μm.
From the viewpoint of making the joint of the adjacent laminated portions 10 more difficult to be visually identified, the gap S is more preferably from 10 μm or more and 200 μm or less, more preferably from 10 μm or more and 100 μm or less, and particularly preferably from 10 μm or more and 50 μm or less. When the gap S is 50 μm or less, the joint of the adjacent laminated portions 10 is almost invisible.
In this case, L represents a length of a side in an X direction of the base material 20, and x represents a length of a longer side of two sides of the laminated portion 10 that are substantially parallel to the X direction. Further, dy represents a length in the Y direction between two points at which lines drawn perpendicular to the X direction meet a shorter side of the two sides of the laminated portion 10 that are substantially parallel to the X direction. dy corresponds to a gap in the Y direction.
Under the above conditions, when n representing the closest value that satisfies L≤n×x (n is an integer of 2 or more) is obtained, 50 μm≤n×dy≤500 μm is preferably satisfied. In other words, when the number of the laminated portions 10 arranged in the X direction is n, it is preferable that 50 μm≤n×dy≤500 μm be satisfied. In this case, the size of the multilayer structure, the number of laminated portions, and the size of the gap have the most preferable relationship, and the gap becomes less conspicuous.
As can be seen from the relationship of 50 μm≤n×dy≤500 μm, it is necessary to reduce the gap dy in the Y direction as the number n of the laminated portion 10 in the X direction increases. That is, as the number n of the laminated portions 10 arranged in the X direction is larger, the laminated portions need to be arranged densely so that the gap dy in the Y direction becomes smaller. Iif the laminated portions arranged in this manner, the gap becomes less conspicuous.
Since handling becomes difficult the size of the laminated portion 10 as too large or too small, it is preferable that the laminated portion 10 be of an appropriate size that is easy to handle. As an example of the preferred size of the laminated portion 10, the lengths in the X direction and the Y direction are each approximately 10 cm.
As described above, the multilayer structure 1 includes a plurality of laminated portions 10 arranged on the base material 20. The laminated portion 10 has the resin layer 11 and the glass layer 14 laminated over the resin layer 11 through the adhesive layer 12, and the metal layer 13 is formed on the surface of the glass layer 14 that is oriented toward the adhesive layer 12. The thickness of the glass layer 14 is 10 μm or more and 300 μm or less.
In other words, the thickness of the glass layer 14 is small in each laminated portion 10 of the multilayer structure 1, and the distance between the surface of the glass layer 14 and the metal layer 13 is very close. Therefore, in the multilayer structure 1, it is possible to project a clear image by solving the problem of a conventional sheet glass in which an image is doubly reflected. The thinner the glass layer 14 is, the more difficult it is to visually identify the joints of the adjacent laminated portions 10.
In addition, by the structure, in which the plurality of laminated portions 10 are fixed to the base material 20, it is possible to provide a large area multilayer structure, which can project a clear image and can be used as a thin glass mirror.
Here, materials and the like of each part of the multilayer structure 1 will be described.
The resin layer 11 is a base material on which the glass layer 14 and the like are laminated, and the resin layer 11 has flexibility. The resin layer 11 includes one or a plurality of layers.
Examples of the material of the resin layer 11 include polyester resins such as polyethylene terephthalate resins and polyethylene naphthalate resins, cycloolefin resins such as norbornene resins, polyether sulfone resins, polycarbonate resins, acrylic resins, polyolefin resins, polyimide resins, polyamide resins, polyimide amide resins, polyarylate resins, polysulfone resins, polyether imide resins, cellulose resins, and the like. Among these, polyethylene, terephthalate, triacetyl cellulose and acrylic are preferably used because of the toughness of the resin. From the viewpoint of industrialization, it is particularly preferable, to use a film-like polyethylene terephthalate.
The color of the resin layer 11 is not particularly specified, and may be transparent or opaque. The resin layer 11 may contain an additive such as inorganic particles. The thickness of the resin layer 11 (the total thickness when the resin layer 11 includes a plurality of layers) may be in the range of 10 μm or more and 1000 μm or less, preferably 25 μm or more and 500 μm or less, more preferably 25 μm or more and 300 μm or less, from the viewpoint of flexibility.
The glass layer 14 is not particularly specified, and an appropriate glass layer can be adopted depending on the purpose. The glass layer 14 may be, for example, soda lime glass, boric acid glass, aluminosilicate glass, quartz glass or the like according to the classification by composition. According to the classification by the alkali component, alkali-free glass and low alkali glass are given. The content of the alkali metal component (For example, Na2O, K2O, Li2O) of the glass is preferably 15 wt % or less, more preferably 10 wt % or less.
The thickness of the glass layer 14 is preferably 10 μm or more in consideration of the surface hardness, airtightness, and corrosion resistance of the glass. The glass layer 14 is preferably flexible like a film and has a thickness of 300 μm or less to prevent double reflection of an image and to project a clear image. The thickness of the glass layer 14 is more preferably 30 μm or more and 200 μm or less, and particularly preferably 50 μm or more and 100 μm or less.
The light transmittance of the glass layer 14 at a wavelength of 550 nm is preferably 85% or more. The refractive index of the glass layer 14 at a wavelength of 550 nm is preferably 1.4 to 1.65. The density of the glass layer 14 is preferably 2.3 g/cm3 to 3.0 g/cm3, and more preferably 2.3 g/cm3 to 2.7 g/cm3.
The method of forming the glass layer 14 is not particularly specified, and an appropriate method can be adopted depending on the purpose. Typically, the glass layer 14 can be prepared by melting a mixture containing a main raw material such as silica or alumina, an antifoaming agent such as mirabilite and antimony oxide, and a reducing agent such as carbon at a temperature of approximately 1400°C. to 1600°C., molding the mixture into a thin plate, and then cooling the thin plate. Examples of the method of forming the glass layer 14 include a slot-down draw method, a fusion method, and a float method. The glass layer formed in a plate-like shape by these methods may be chemically polished with a solvent such as hydrofluoric acid, as required, for thinning or enhancing smoothness.
The metal layer 13 is formed on the surface of the glass layer 14 that is oriented toward the adhesive layer 12. The metal layer 13 is a layer that reflects visible light incident through the glass layer 14. As the material of the metal layer 13, a material having a high visible light reflectance is preferable, for example, aluminum, silver, silver alloy, or the like. The thickness of the metal layer 13 is not particularly specified, but is, for example, approximately 10 nm to 500 nm. The metal layer 13 can be formed by, for example, a sputtering method, a vapor deposition method, a plating method, or the like. A functional layer such as an antifouling layer, an antireflection layer, and a conductive layer may be provided on a surface of the glass layer 14 (a surface of the glass layer 14 on which the metal layer 13 is not formed).
Any suitable adhesive may be used as the adhesive layers 12 and 15. From the viewpoint of appearance, the thickness of the adhesive layers 12 and 15 is preferably 0.5 μm or more and 25 μm or less, more preferably 0.5 μm or more and 20 μm or less, and more preferably 0.5 μm or more and 5 μm or less.
As the adhesive layers 12 and 15, for example, an acrylic pressure-sensitive adhesive, a silicone pressure-sensitive adhesive, a rubber pressure-sensitive adhesive, an ultraviolet curable acrylic adhesive, an ultraviolet curable epoxy adhesive, a thermosetting epoxy adhesive, a thermosetting melamine adhesive, a thermosetting phenolic adhesive, an ethylene vinyl acetate (EVA) interlayer, a polyvinyl butyral (PVB) interlayer, or the like can be used. Among these, an epoxy adhesive for cohesion and durability may be preferably used.
In the present specification, a pressure-sensitive adhesive refers to a layer that has adhesiveness at room temperature and adheres to the adherent under light pressure. Accordingly, even when the adherend adhered to the pressure-sensitive adhesive is peeled off, the pressure-sensitive adhesive retains a practical tack strength. An adhesive, on the other hand, refers to a layer that can bind a substance by intervening between the substances. Therefore, when the adherend adhered to the adhesive is peeled off, the adhesive does not have a practical adhesive strength.
The base material 20 is made of a material having higher rigidity than that of the laminated portion 10 in order to prevent the laminated portion 10 from bending. Examples of the material of the base material 20 include resin, glass, and metal. Among these, it is preferable to use glass because the dimensional change is small and the smoothness is excellent. Since the base material 20 is a lower layer of the metal layer 13 when viewed from the glass layer 14 side, the base material 20 does not have a function of a mirror.
When the base material 20 is thin, the entire multilayer structure 1 could become bent, and the image reflected on the multilayer structure 1, which is a mirror, is distorted. Therefore, when the area of the upper surface 20a of the base material 20 is S (m2) and the thickness of the base material 20 is T (mm), it is preferable to set the thickness T within a range satisfying 20S≥T≥S. Thus, the bending of the multilayer structure 1 can be prevented, and it is possible for the image reflected on the multilayer structure 1 to not be readily distorted.
The laminated portion 10 is obtained, for example, by laminating the glass layer 14, on which the metal layer 13 is formed by sputtering or the like, on the resin layer 11 via the adhesive layer 12, and dividing the glass layer into pieces in predetermined shapes by pressing or the like. Alternatively, the glass layer 14 on which the resin layer 11 and the metal layer 13 are formed may be continuously laminated by using a roll-to-roll process via the adhesive layer 12, and then divided into pieces in an any desired size by pressing or the like. The individually divided laminated portions 10 are arranged on the base material 20 through the adhesive layer 15 by a laminator or the like.
The multilayer structure 1 can be used as a thin glass mirror, and specifically used, for example, as a full-length mirror, a curved surface of a large security mirror, a mirror for solar thermal power generation, an optical camouflage mirror, a lighting mirror, etc. The same applies to the multilayer structures exemplified below.
Modifications of the first embodiment illustrate examples of a multilayer structure having a structure different from that of the first embodiment. In the modifications of the first embodiment, description of the same components as those of the above-described embodiment may be omitted.
The colored layer 122 a layer, that coats the upper surface of the base material 20 with an opaque colored material, and the thickness of the layer is approximately 1 μm. The colored layer 22 may be a layer having a light scattering property with respect to light incident from the gap S, and may be, for example, a metallic silver or white layer. Here, the light scattering property is property that generates light traveling in a random direction by scattering at least a part of the light incident from the gap S. The colored layer 22 can be formed by forming a coating liquid, in which metal particles such as silver nanoparticles are dispersed, on the upper surface 20a of the base material 20 by a spray coating method, a spin coating method, or the like. Since the metal particles are dispersed in the colored layer 22, the light scattering property can be enhanced.
Since the light-scattering colored layer 22 is formed on the upper surface 20a of the base material 20 in this manner, light incident from the gap S is scattered. Therefore, the joints can be made more difficult to be visually identified as compared with the case where the size of the gap S formed at the joints of the adjacent laminated portions 10 is the same, and the colored layer 22 not formed. Needless to say, it is more preferable to use a colored layer in combination with measures for reducing the gap S.
The buffer layer 17 is a cushioning layer located between the base material 20 and the resin layer 11. The thickness of the buffer layer 17 is preferably 100 μm or more and 2000 μm or less from the viewpoint of developing a good cushioning property. Examples of the material of the buffer layer 17 include a urethane resin and various foaming materials. Examples of the various foaming materials include a polyolefin resin, a polypropylene resin, a polystyrene resin, a polyethylene resin, and the like. A commercially available foamed sheet may be used as the buffer layer 17. Examples of commercially available foamed sheets include SCF (registered trademark) manufactured by Nitto Denko Corporation. The adhesive layer 16 can be any adhesive or pressure-sensitive adhesive exemplified as the adhesive layers 12 and 15.
Thus, providing the buffer layer 17 as a lower layer of the resin layer 11, the cushioning property of the multilayer structure 1B can be enhanced, and the impact applied to the multilayer structure 1B from the outside can be softened. Instead of the buffer layer 17 or in addition to the buffer layer 17, a layer having another function such as a heat insulating layer may be laminated.
In the multilayer structure 1A illustrated in
As illustrated in
As described above, it is not necessary to have one type of laminated portion constituting the multilayer structure, and two types of laminated portions may be used. Alternatively, the multilayer structure may have three or more types of laminated portions.
The planar shape of the laminated portions are not limited to a rectangular shape, but may be a triangular shape, a hexagonal shape, or the like, or may be a mixture of these shapes. The shape of the multilayer structure as a whole does not have to be rectangular, and laminated portions having different planar shapes can be mixed together to form any desired shape, for example.
The multilayer structure need not be in a planar shape parallel to the XY plane, but may be curved, for example, in a semicylindrical shape or a dome-like shape. Here, the dome-like shape means a shape in which the position of the surface of the multilayer structure (the surface of the glass layer) in the Z direction gradually increases from the periphery toward the center.
In the case of
As described above, since there are places where the joints of the adjacent laminated portions are discontinuous with each other, it is possible to make the joints more difficult to visually identify even when the sizes of the gaps S are the same. Although
Although the preferred and the like have been described in detail above, various modifications and substitutions can be made to the embodiments and the like without departing from the scope of the claims.
This international application claims priority under Japanese Patent Application No. 2020-059418, filed with the Japanese Patent Office on Mar. 30, 2020, and the entire contents of Japanese Patent Application No. 2020-059418 are incorporated herein by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-059418 | Mar 2020 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/009468 | 3/10/2021 | WO |
